Expanding arbor



C. F. SHERMAN.

EXPANDING ARBOR- .AFPLICATION mm mm n. 1919. RENEWED sum: 1. 1920.

Patented July 20; 1920.

fnuenfor: C'oril's flfifierma n UNITED STATES PATENT OFFICE.

CORTIS F. SHERMAN, F HARTFORD, CONNECTICUT, ASSIGNOR T0 HESS-BRIGHT MANUFACTURING COMPANY, OF PHILADELPHIA, PENNSYLVANIA, A CORPO- RATION OF DELAWARE.

EXPANDING ARBOR.

- Specification of Letters Patent.

Patented July 20, 1920.

Application filed July 11, 1919, Serial No. 310,088. Renewed June 7, 1920. Serial No. 387,158.

I To all whom it may concern:

Be it known that I, CoRTIs F. SHERMAN,

' a citizen of the United States, residing at Hartford, in the county of Hartford and State of Connecticut, have invented certain new and useful Improvements in Expanding Arbors, of which the following is a specification.

This invention relates to arbors'for rigidly supporting annular pieces of work, particularly those which are to be machined or Worked upon in some manner, an object of the invention being to form the shell of such an arbor with a closed chamber and locate and support a reciprocatory expander therein in such manner that the working parts are completely incased within such closed chamber, the expander positively guided and the shell and expander rigidly bonded together when the work seat is expanded for holding the work.

The drawings accompanying this specification illustrate one practicable embodiment of my invention, in which drawings-- Figure 1 is aview partly in central longitudinal section and partly in elevation of my improved arbor, showing the same inits work clamping or holding position.

Fig. 2 is a cross sectiontaken on a plane at about line'2-2 of Fig. 1, the expander being omitted.

Fig. 3 showsthe expander in elevation, and

Fig. 1 is an end elevation from the lefthand end of Fig. 1. r

The shell 5 of the arbor is formed with a hollow interior or closed chamber 6 and with a substantially cylindrical external work receiving face or work seat 7. This face preferably has a' slight taper from the shoulder or back stop 8 toward the outer or front end of the arbor. piece of work in the present instance, the inner ring of a ball bearing, is indicated by dotted lines 9 {in position on this work seat 7 and in enthe forward or clamping-movement of the expander plug and afterward when the shell and work seat have been expanded and the v piece of work securely held in position on the arbor. In using the terms backward and forward, front end and rear end, considerable confusion may arise owing to the fact that what is the processionalmovement of the expander is toward what is really the back end of the arbor and that the recessional or unclamping movement of the plug is toward what is 'thefront end of the arbor. With this brief explanation in mind it is believed that the apparent'confusion will be obviated. The expander plug 10 is shown formed of considerable weight in relation to its size and provided upon its exterior with a tapering face which mates with a suitably formed tapering face upon the'interior of the shell of the arbor. -The rear end of the shell is provided in'the present illustration with an integral closure 11 having a central bore. The front end of the shell is provided in the illustration with a removable closure 12 provided. with a central bore in alinement with the bore of the integral closure 11. In these bores is rigidly supported a guiding bar 13, upon which is mounted for reciprocation the expanding plug 10, the plug being provided with an interior bore 14 of such dimensions relative to the bar 13 that. it has a close working fit therein sufiiciently free topermit the reciprocation of the expander, but also sufficiently close to prevent any lateral movement of the plug. In the illustration the bar 13 is provided with an integral collar 15, I

the rear face of which engages the front face of the end closure .11 and is clamped thereto by a suitable heavy nut '16, having screw threaded engagement with an extending end of the bar. ,A disk ofelastic material 17 is shown facing the end closure 12 for receiving the impact of the expander in its recessional movement. Lathe centers 18, 18, are provided in the ends of the bar 13. By this means the force ofholding the arbor to the live spindle is carried directly by a solid partand in nowise interferes with the efficient action of the shell. The end closures or more correctly, the end walls of the shell, have such a close fit with the bar '13 that the entrance of fluids or grit is practically impossible. The wall of the arbor shell illustrated in thedrawing is so formed that although it is unbroken it is capable of circumferential expansion and contraction, particularly under the influence of force applied from within the chamber ofthe shell, the expansion being caused by the processional movement of the expander plug driving its tapering surface against the tapering wall of the shell, the contraction resulting from the natural elasticity of the metal of the shell when relieved from the expanding force. In practice I have found it desirable to form a shell with a series of longitudinal external ribs 20 set. ofi' by a largement, which aiiords the back stop face 8.

The taper face on the inner wall of the shell for the engagement of the taper face of the expander 10 is provided on the crests of the ribs 22. This face, or rather, the series of faces, is represented by the reference character 24, Fig. 2. When it is desired to apply a piece of work, as for instance, thering 9 of the arbor, the arbor is preferably placed in an upright position with the back end, the nut 16 in the illustration, resting upon the work bench and the expander plug retracted from its shell expanding position. The ring is then slipped over the outer or front end of the arbor and over the work seat 7 and preferably resting against the back stop 8. The

arbor is thenraised a short distance fronrthe work bench and permitted to drop forclbly against the bench or a block of wood thereon.

- The impact of this blow imparts the excursion or processional movement to the expander plug, causing this to advance against the taper seat 24 and move toward the rear end of the arbor, guided nevertheless by the bar 13. The entireshell of the arbor and the plug are through the instrumentality of the bar thus completely bonded together in a rigid structure. The wall of the shell is expanded, expanding the work seat against the work and holding this securely in position. It is obvious that any unevenness in the bore of the work carried on the work seat will not throw the arbor out of true when the plug is forced to this expandingposition. It will also be obvious that pressure applied to one side of the work carried by the arbor is evenly distributed throughout the entire structure'without any tendency to cause the working point of the work to pass through an eccentric orbit. When it is de sued to remove the work the arbor is taken from the centers and the frontend, represented by the end wall 12, is permitted to drop upon the work bench or is given a blow by some elastic body, the impact of which blow causes the recessional movement of the expander plug, drawing this toward the end represented by 12 and: preferably against the cushioning member 17. The mo- Inentum imparted to the work by the impact.

of the blow causes this-immediately upon the wall of the shell assuming its former position to fall oif, whereupon a new piece of work is placed in position and the expanding operation is repeated.

As the lathe centers 18 are formed in the extending ends of the supporting rod, it will be seen that when these become worn or injured, the arbor itself does not have to be repaired or renewed but that the bar only requires repair or an interchangeable one substituted in its place.

It is to be understood that the device 2 side walls for expanding the same and the work seat.

2. .An expanding arbor,icomprising a shell having elastic side walls, provided on the exterior with a work seat, the walls of the shell forming a closed chamber, a guiding bar carried by the end walls of the shell, and a weighted expander plug mounted .on said bar for reciprocation within the chamber and adapted upon its excursion to act upon ,the arbor for expanding the same, the parts being so organized that the impact of a blow uponone end of the arbor effects the excursion of the expander.

3. An expanding arbor, comprising a shell I having elastic side walls, provided on the f exterior with a work seat, the walls of the shell forming a closed chamber, a guiding bar carried by the end walls of the shell, and a weighted expander plug mounted on said bar for reciprocation within the chamber and adapted upon its excursion to actupon the arbor for expanding the same, the parts being so organized that the impact of a blow upon one end of the arbor effects the excursion of the expander and the impact of a blow on the other end of the arbor efl'ects the recession of the expander. l y

4. An expanding arbor, comprising a shell, having rigid end walls, elastic side walls, and upon its exterior a work seat and a work Stop at the back of the seat, the seat tapering from such stop toward the front, the wall of such shell forming a closed chamber tapering from the front and t0 ward the back end, a guiding bar carried by the end walls, and a similarly tapering reciprocatory expander plug inclosed in said chamber and mounted on said bar.

5. An expanding arbor, comprising a shell, having rigid end walls, elastic side walls, and upon its exterior a work seat and a work stop at the back of the seat, the seat tapering from such stop toward the front, the wall of such shell forming a closed chamber tapering from the front end toward the back end, a guiding bar carried by the end walls and extending through the same and there provided with lathe centers.

6. An expanding arbor, comprising a a shell, having rigid end walls, elastic side walls, and upon its exterior a work seat and a work stopat the back of the seat, the seat tapering from such stop toward the front, the wall of such shell forming a closed chamber tapering from the front end toward the back end, an interchangeable guiding bar carried by the end walls and extending through the same and there provided with lathe centers.

In testimony whereof, I have hereunto 

